An-Najah National University Faculty of Graduate Studies
Epidemiology of Dermatophyte Infections in Palestine: an update Study
By Eman Yousef Mohammed Hussein
Supervisor Dr. Sami Yaish Co-supervisor Dr. Hisham Arda
This Thesis is Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Life Sciences (Biology), Faculty of Graduate Studies, An-Najah National University, Nablus, Palestine. 2013
iii Dedication
To Allah, To my dear mother, father, sisters, brothers, hasband and my little sweet daughter and son for their patience and encouragement, with love and respect iv Acknowledgments
I would like to thank my supervisors Dr. Sami Yaish and Dr. Hisham Arda for their supervision, guidance, and encouragement throughout the work.
My thanks also go to Prof. Mohammed S. Ali Shtayeh and Dr. Rana Jamous of the Biodiversity and Environmental Research Center, BERC,
Til, for their advice, and guidance from the very early stage of this research as well as giving me extraordinary experiences throughout the work.
I would also like to thank my colleagues Omar Mallah, and Salam
Abu Zeitoun from BERC for providing support.
I am grateful to the Biodiversity and Environmental Research Center, BERC, Til, for the financial support.
Above all, I would like to thank my husband for his personal support and great patience at all times. My parents, brothers and sisters have given me their unequivocal support throughout, as always, for which my mere expression of thanks likewise does not suffice. v ﺍﻹﻗﺭﺍﺭ
ﺃﻨﺎ ﺍﻝﻤﻭﻗﻌﺔ ﺃﺩﻨﺎﻩ ﻤﻘﺩﻤﺔ ﺍﻝﺭﺴﺎﻝﺔ ﺍﻝﺘﻲ ﺘﺤﻤل ﻋﻨﻭﺍﻥ : : Epidemiology of Dermatophyte Infections in Palestine: an update Study
ﻭﺒﺎﺌﻴﺔ ﺍﻷﻤﺭﺍﺽ ﺍﻝﺠﻠﺩﻴﺔ ﻓﻲ ﻓﻠﺴﻁﻴﻥ : ﺩﺭﺍﺴﺔ ﻝﻠﺘﺤﺩﻴﺙ
ﺃﻗﺭ ﺒﺄﻥ ﻤﺎ ﺍﺸﺘﻤﻠﺕ ﻋﻠﻴﻪ ﻫﺫﻩ ﺍﻝﺭﺴﺎﻝﺔ ﺇﻨﻤﺎ ﻫﻲ ﻨﺘﺎﺝ ﺠﻬﺩﻱ ﺍﻝﺨﺎﺹ، ﺒﺎﺴﺘﺜﻨﺎﺀ ﻤـﺎ ﺘﻤـﺕ
ﺍﻹ ﺸﺎﺭﺓ ﺇﻝﻴﻪ ﺤﻴﺜﻤﺎ ﻭﺭﺩ، ﻭﺃﻥ ﻫﺫﻩ ﺍﻝﺭﺴﺎﻝﺔ ﻜﻜل، ﺃﻭ ﺃﻱ ﺠﺯﺀ ﻤﻨﻬﺎ ﻝﻡ ﻴﻘﺩﻡ ﻤﻥ ﻗﺒل ﻝﻨﻴل ﺃﻱ ﺩﺭﺠﺔ ﺃﻭ ﻝﻘﺏ ﻋﻠﻤﻲ ﺃﻭ ﺒﺤﺜﻲ ﻝﺩﻯ ﺃﻴﺔ ﻤﺅﺴﺴﺔ ﺘﻌﻠﻴﻤﻴﺔ ﺃﻭ ﺒﺤﺜﻴﺔ ﺃﺨﺭﻯ . .
Declaration
The work provided in this thesis، unless otherwise referenced is the researcher's own work، and has not been submitted elsewhere for any other degree or qualification.
ﺍﺴﻡ ﺍﻝﻁﺎﻝﺒﺔ : :Student's name
ﺍﻝﺘﻭﻗﻴﻊ : :Signature
ﺍﻝﺘﺎﺭﻴﺦ : :Date vi List of Abbreviations HCL Hydrochloric acid DMSO Dimethyl sulfoxide dNTP`s Deoxynucleotide triphosphates EDTA Ethylenediamine tetraacetic acid Kac Potassium acetate KOH Potassium hydroxide g Microgram l Microliter NaCl Sodium chloride PCR Polymerase chain reaction RAPD Random amplification of polymorphic DNA S.D. H2O Sterile distilled water SDA Sabouraud dextrose ager SDS Sodium dodecyl sulfate TAE Tris base, acetic acid and EDTA Tris (hydroxymethyl)aminomethane
vii Table of Contents No. Content Page Dedication iii Acknowledgment iv Declaration v List of abbreviations vi List of contents vii List of tables ix List of figures x Abstract xi Chapter One: General Introduction 1 1.1 General properties of fungi 2 1.2 Dermatophytes 3 1.3 Ecology 4 1.4 Geographical distribution of the dermatophytes 4 1.5 Dermatophytosis transmission 5 Symptoms and clinical signs of dermatophytosis disease 1.6 7 in human 1.7 Clinical manifestations 7 Multifocal infections tinea pedis, tinea nail and tinea 1.8 9 cruris 1.9 Epidemiology 11 1.9.1 Dermatophytes epidemiology in Palestine 12 1.9.2 Etiological agents 13 1. 10 Diagnosis 15 1.11 Identification of dermatophytes 15 1.11.1 Conventional approaches 15 1.11.2 Molecular biological methods 17 1.12 Aims and objectives 20 Chapter Two: Materials and Methods 21 2.1 Epidemiology of dermatophytes infections 22 2.1.1 Sample collection 22 2.1.2 Direct examination 22 2.1.3 Cultures and isolation of dermatophytes 23 Genotypical pattern of dermatophytes strains by using 2.2 23 RAPD analysis primers 2.2.1 Fungal DNA isolation 23 2.2.2 RAPD assays 24 2.2.3 RAPD PCR amplification program 25 2.2.4 RAPD PCR products scoring 25 2.2.5 Data analysis 26 viii No. Content Page Chapter Three: Results and Discussion 27 3.1 Epidemiology of dermatophytes infections 28 Genotypical pattern of dermatophytes strains by using 3.2 36 RAPD analysis primers 3.2.1 RAPD PCR amplification 36 3.2.2 RAPD Data analysis 39 References 43 Appendix 56 ﺏ ﺍﻝﻤﻠﺨﺹ
ix List of Tables No. Table Page Details of patients with reference to clinical Table (3.1) 29 manifestation and sex. Table (3.2) Prevalence pattern of dermatophytic fungi (n, %) 33 Frequency of causative agents causing Table (3.3) dermatophytic infections isolated from positive 33 cultures Prevalence pattern of dermatophytic fungi in Table (3.4) 35 multifocal infections (n, %) Table (3.5) Similarity matrix 41
x List of Figures No. Figure Page Macroconidia of Microsporum canis under Figure (3.1) 29 direct microscopy (400 x) Microconidia of Trichophyton mentagrophytes Figure (3.2) 30 under direct microscopy (400 x) Microconidia of Trichophyton mentagrophytes Figure (3.3) 31 under direct microscopy (400 x) Both sides of primary culture of Microsporum Figure (3.4) 32 canis Both sides of primary culture of Trichophyton Figure (3.5) 32 mentagrophytes Both sides of primary culture of Trichophyton Figure (3.6) 32 rubrum Example of RAPD banding patterns generated Figure (3.7) 37 in first 15 isolates of M.canis using OPA02 Example of RAPD banding patterns generated Figure (3.8) 37 in first 15 isolates of M.canis using OPA01 Example of RAPD banding patterns generated Figure (3.9) 38 in first 15 isolates of M.canis using OPA03 Example of RAPD banding patterns generated Figure (3.10) 38 in first 15 isolates of M.canis using OPA04 Example of RAPD banding patterns generated Figure (3.11) 39 in first 15 isolates of M.canis using OPA05 Dendrogram using average linkage (Within Figure (3.12) 42 Group)
xi Epidemiology of Dermatophyte Infections in Palestine: an update Study By Eman Yousef Mohammed Hussein Supervisor Dr. Sami Yaish Co-supervisor Dr. Hisham Arda Abstract
Background : Dermatophytes are a group of morphologically and physiologically related molds some of which cause well defined infections: dermatophytoses (tineas or ringworm) .They have two important properties: they are keratinophilic and keratinolytic. This means they have the ability to digest keratin in vitro in their saprophytic state and utilize it as a substrate and some of them can invade tissues in vivo and cause tineas.
Objectives : This study was designed to determine the epidemiology including prevalence and occurrence of causative agents of dermatophytosis in patients in Palestine; detecting any changes in the etiological agents during the last 28 years; studying the effective factors such as socioeconomic condition, age, contact with animals and others; studying the correlation between multifocal infections tinea pedis , tinea nail and tinea cruris . The study was also aimed at genotyping identification and how can be used as a molecular tool for rapid diagnosis for dermatophytes also to study the diversity during different dermatophytes species and within the same specie specially Microsporum canis ,
Trichophyton rubrum and Trichophyton mentagrophytes . Genetic studies by random amplification of polymorphic DNA (RAPD) have been used to xii detect polymorphism of dermatophytes. The genotypical analysis was performed using the RAPD method as rapid molecular tool for diagnosis.
Results: In this study, a total number of 220 samples from 188 patients were examined ((137 males (72.9%), and 51 females (27.1%)). Tinea Capitis (27.7%) was the predominant clinical manifestation followed by tinea pedis (23.4%), tinea nail (22.3%), tinea cruris (20.2%) and tinea corporis(6.4%). The dominant causative agent was Microsporum canis 104 samples from 138 (75.36%) followed by Trichophyton rubrum 31 samples from 138 (22.5%) then Trichophyton mentagrophytes 3 samples from 138
(2.1%). The RAPD results showed that all analyzed strains are mainly from three genotypes of Microsporum canis , two genotypes of Trichophyton rubrum and one genotype of Trichophyton mentagrophytes . Thus, based on analysis of the RAPD data, a correlation can be shown between the genotypical patterns of the strains of Microsporum canis also between the strains of Trichophyto rubrum and Trichophyton mentagrophytes from
Palestine.
Conclusions: The results showed that the predominant causative agent of dermatophytes specis was Microsporum canis . This change could be due to several factors as activity related to human and animals’ hygiene, interaction between human and human, animal and soil, and changing population over the times. 1
CHAPTER ONE GENERAL INTRODUCTION 2 CHAPTER ONE GENERAL INTRODUCTION
1.1 General properties of fungi
The kingdom Fungi contains many organisms such as dermatophytes, yeasts, Penicillium spp., morels and gilled mushrooms. It includes more than 100,000 species. Fungi are considered as a separate kingdom of living organisms at the same level as the animals and the plants (Koichi et al. , 1999).
Fungi are eukaryotes, heterotrophic organisms, and spread as colonies of isolated cells (yeasts) or mycelium (a mycelium is a multicellular filament (or hypha) which branches to form a network). Each fungus cell contains one or several haploid or diploid nuclei, fungal cells are delimited by a β 1 3 and β 1 6 glucan wall and chitin. Fungi reproduce both sexually and asexually often resulting in the production of spores which are wind disseminated depending on the species and conditions.
Spores are generated on hyphae or in micro or macroscopic sporangia which show a limited tissue differentiation. The asexual and sexual forms in the same species are morphologically very different. The asexual forms of fungi are called anamorphs and the sexual forms are called teleomorphs. The term of “holomorph” is used to designate the total organism and a fungal colony where an ananmorph and the teleomorph coexist. A holomorph can give rise to an exclusive anamorph species by loss of the teleomorph during evolution. The term of “synanamorph” is used to designate two different anamorphs of the same species (Ajello et al ., 1966). 3
1.2 Dermatophytes
Dermatophytes are a group of morphologically and physiologically related molds some of which cause well defined infections: dermatophytoses (tineas or ringworm) (Liu et al ., 2011; Azab et al ., 2012). They have the ability to digest keratin in vitro in their saprophytic state and utilize it as a substrate and some of them can invade tissues in vivo and cause tineas. However, their morphology in the parasitic growth phase is different from the morphology exhibited in culture or in vitro (McPherson et al ., 2008).
Dermatophytes as saprophytes reproduce asexually by simple sporulation of arthroconidia, microconidia and/ or macroconidia which are produced from specialized conidiogenous cells. They also exhibit a range of vegetative structures with typical arrangement on hyphae, chlamydospores, spirals, antler shaped hyphae (chandeliers), nodular organs, pectinate organs and racquet hyphae (Emmons, 1934; Ajello et al .,
1966).
In presumptive identification of a dermatophyte culture, five important colony characteristics should be taken into consideration, when it is one to three weeks old: rate of growth , general topography (flat, heaped, regularly or irregularly folded) , texture (yeast like, glabrous, powdery, granular, velvety or cottony) , surface pigmentation and reverse pigmentation (Ajello et al ., 1966 ). 4
Based on the above criteria dermatophyte species can be classified, particularly on differences in conidial morphology, into three genera within the Fungi Imperfecti (or Deuteromycotina) namely: Epidermophyton ,
Microsporum , and Trichophyton (Emmons, 1934; Caputo et al ., 2001; Ghannoum et al ., 2003).
1.3 Ecology
Dermatophytes have been divided into three ecological groups: geophiles, zoophiles and anthropophiles (Georg, 1959; Achterman et al ., 2011). Some of these fungal pathogens probably evolving from their natural habitat in the soil have developed host specificity, resulting in these three groups. Individual dermatophytes differ considerably in their host range and importance as agents of disease in man and animals. The differences in host specificity have been attributed to the differences in keratin of the hosts (Rippon, 1982).
Geophiles are primarily soil inhabiting and only rarely encountered as agents of ringworm, with the exception of Microsporum gypseum . Zoophiles are essentially animal pathogens, although they may cause infection in humans. Anthropophiles are restricted to man, very rarely infecting animals (Georg, 1959).
1.4 Geographical distribution of the dermatophytes
Variations in the distribution pattern of dermatophytes infection among different countries was reported (Ayadi et al ., 1993; Staats & 5
Korstanje, 1995; Weitzman & Summerbell, 1998; Ellabib et al ., 2002). This distribution pattern of dermatophytes infection in different part of the world has been attributed to climatic factors, life style, and prevalence of immunodeficiency diseases in the community and also the reluctance of patients to seek treatment because of embarrassment or minor nature of disease unless the condition becomes sufficiently serious to affect the quality of life (Al sheikh, 2009).
Dermatophytosis, especially tinea capitis, tinea corporis and tinea cruris, occurs worldwide but is very common in tropical countries because dermatophytes grow best in warm and humid environments (Frieden & Howard, 1994). The geographic distribution varies with the organism. Microsporum canis , Microsporum nanum , Trichophyton mentagrophytes and Trichophyton verrucosum occur worldwide, while Trichophyton mentagrophytes var. erinacei is limited to France, Great Britain, Italy and New Zealand (Ginter Hanselmayer et al ., 2007) and Trichophyton simii
(found in monkeys) occurs only in Asia (Macura, 1993).
1.5 Dermatophytosis Transmission
Infection occurs by contact with arthrospores (asexual spores formed in the hyphae of the parasitic stage) or conidia (sexual spores formed in the “free living” environmental stage). Dermatophytes usually begins in a growing hair or the stratum corneum of the skin and they don`t generally invade resting hairs, since the essential nutrients they need for growth were absent or limited. Hyphae spread in the hairs and keratinized skin, 6 eventually developing infectious arthrospores. Transmission between hosts usually occurs by direct or indirect ways. The direct way is by contact with a symptomatic or asymptomatic host. Infective spores in hair and dermal scales can remain viable for several months to years in the environment and fomites such as brushes and clippers which can be important in indirect transmission. Geophilic dermatophytes, such as Microsporum gypseum , are usually acquired directly from the soil (Ajello et al ., 1966). In animals arthrospores are transmitted through direct contact with sick or subclinically infected animals, mainly cats, but also with dogs and other species. In sick animals, the infected hair shafts are fragile and hair fragments containing arthrospores are efficient in spreading the infection. In addition, uninfected cats can passively transport arthrospores on their hair, thereby acting as a source of infection. Risk factors include introduction of new animals into a cattery, cat shows, catteries, shelters, mating etc. Indirect contact is important, too; transmission may occur via contaminated collars, brushes, toys etc. Arthrospores are easily spread on dust particles. In households with infected cats, the furniture, wallhangings, clothes and even rooms without access for cats become contaminated.
Outdoor cats, especially in rural areas, can be sometimes infected with agents other than Microsporum canis dermatophytes . Microsporum gypseum is a geophilic fungus living in soil to which cats are exposed by digging. Trichophyton mentagrophytes and Trichophyton quinckeanum are prevalent in small rodents and their nests, and Trichophyton verrucosum is isolated from cattle (Brumm, 1985). 7
1.6 Symptoms and Clinical signs of Dermatophytosis Disease in Human
Dermatophytes generally grow only in keratinized tissues such as hair, nails and the outer layer of skin. The incubation period is one to two weeks. The fungus usually stops spreading where it contacts living cells or inflammation areas. Mucus membranes are not affected. The clinical signs may vary, depending on the region affected. In humans, pruritus is the most common symptom. The skin lesions are usually characterized by inflammation that is most severe at the edges, with erythema, scaling and occasionally blister formation. Central clearing is sometimes seen, particularly in tinea corporis; this results in the formation of a classic “ringworm” lesion. On the scalp and facial hair, there may be hair loss.
Dermatophytes acquired from animals or the soil generally produce more inflammatory lesions in humans than anthropophilic dermatophytes. Dermatophytoses in humans are referred to as “tinea” infections, and are named with reference to the area of the body which is involved (Enemuor & Amedu, 2009).
1.7 Clinical manifestations
A wide range of clinical features have been presented by dermatophytosis, which are influenced by many factors mainly depends on the site of infection, the species, size of inoculum and the host’s immune status. Instead of a single organism causing one sign of the disease, several 8 species can, in fact, result in a single disease manifestation (Hiruma & Yamaguchi, 2003). The various clinical features are as follows:
a) Tinea capitis: Ringworm of the scalp, where spores are formed within the hair shaft – endothrix infection or outside it – ectothrix infection and caused by Microsporum specially Microsporum canis and some of Trichophyton species (Fuller et al. , 2003).
b) Tinea Barbae: Infection of the bearded area caused mainly by Trichophyton mentagrophytes and Trichophyton verrucosum.
c) Tinea Manuum: Palms infection, mainly caused by Trichophyton rubrum.
d) Tinea Favosa: Chronic, severe infection of the scalp in humans with crust formation around hair shafts. It is caused by Trichophyton schoenleinii and is common in Eurasia and Africa.
e) Tinea Unguium (onychomycosis): Nail plate invasion, mainly in toenails. It is commonly caused by Trichophyton mentagrophytes and Trichophyton rubrum.
f) Tinea Imbricata: Chronic infection on the body characterised by concentric rings and caused by Trichophyton concentricum. It is geographically restricted to Southeast Asia, Mexico and Central and South America (Weitzman & Summerbell, 1995; Hay, 2003).
g) Tinea Crusis (Jock itch): Ringworm of the groin with occasional
infection of upper thighs and usually seen in men. Frequent etiologic 9
agents are Trichophyton rubrum and Epidermophyton floccosum (Havlickova et al., 2008).
h) Tinea Corporis: Ringworm of the body usually involving the trunk
shoulders or limbs and can be caused by any dermatophyte.
i) Tinea Pedis (Athlete’s foot): Ringworm of the feet especially the soles and presents as scaling or macerations between toes. It is caused by
some of etiologic agents mainly as Trichophyton rubrum and Trichophyton mentagrophytes (Sadri et al., 2000).
1.8 Multifocal infections tinea pedis, tinea nail and tinea cruris Tinea pedis
Tinea pedis presents as pruritic, erythematous, inflamed regions on the feet that may be located on the sole (vesicular type) or lateral aspects
(moccasin type) of the foot and sometimes between the toes (interdigital type). Three main genera of dermatophtye may cause tinea pedis, Trichophyton (T. rubrum, T. mentagrophytes, and T. tonsurans ),
Epidermophyton ( E. floccosum ), and Microsporum (M. canis ) (Hainer, 2003; Vander Straten et. al. , 2003).
Tinea unguum (onychomycosis)
Tinea unguium is a fungal infection of the nail, usually with a dermatophyte, on the matrix, plate, or nail bed commonly associated with tinea pedis. Like tinea pedis infections, T. rubrum is the major cause of subungual onychomycosis. Onychomycosis accounts for about one third of 10 fungal skin infections but only about half of onychomycosis infections are caused by dermatophytes (Roujeau et al ., 2004) .
Tinea cruris
Tinea cruris, or ‘‘jock itch,’’ forms an erythematous, pruritic patch in the groin area that usually spares the scrotum and penis. The leading edge may include follicular papules and pustules, and the etiology agents are T. rubrum,T. mentagrophytes , E. floccosum , and M. canis . The etiology agents are the same as in tinea pedis .
In a closer look for the three multifocal infections, Charif & Elewski in 1997 found that the most cutaneous infections are dermatophytes, and the dermatophyte T. rubrum is the major cause of tinea pedis, Onychomycosis and tinea cruris. Also approximately one half of patients with tinea cruris have coexisting tinea pedis. It was suggested that the plantar surface is frequently an overlooked area and it has been suggested that this part of the foot, in particular, acts as a fungal reservoir from which the infection can spread. Consequently, it is important to assess other areas of skin for a coexisting fungal infection. Concomitant dermatophyte infections are particularly common on the hands (tinea mannum), groin
(tinea cruris) and fingernails (Szepietowski et al ., 2006).
The presence of tinea pedis is also highly correlated with the development of onychomycosis (Sigurgeirsson & Steingrímsson, 2004;
Walling et al ., 2007) and that have been proven in one large 11 epidemiological study, that the presence of either interdigital or moccasin forms of tinea pedis increased the risk of onychomycosis approximately four folds (Sigurgeirsson & Steingrímsson, 2004). In turn, onychomycosis can serve as a reservoir for dermatophytes, which can re infect the skin. The presence of tinea pedis and/or onychomycosis is also a significant risk factor for acute bacterial cellulitis of the leg as well as diabetes related foot and leg complications in at risk individuals (Gupta & Humke, 2000; Roujeau et al ., 2004), so there is a tight correlation between the multifocal infections tinea pedis, tinea nail and tinea cruris.
1.9 Epidemiology
The epidemiology of dermatophyte infection is likely to alter with changing patterns of migration, growth in tourism, and changes in socioeconomic conditions. Dermatophytes endemic to Asia ( Macura, 1993) and Africa (Morar et al. , 2006 ), such as T. soudanense , T. violaceum , and M. audouinii , have increased in frequency in Europe and
North America as a result of migration (Ginter Hanselmayer et al ., 2007). Changes to the epidemiology of causative agents are also a reflection of changing patterns of dermatophytosis.
Knowledge of the predominant causative species provides a clearer understanding of risk factors for superficial fungal infections and future epidemiologic trends. Improvements in living conditions have generally been associated with an increase in zoophilic dermatophyte and in anthropophilic dermatophyte infections. 12
Microsporum canis is a typical zoophilic dermatophyte. As this pathogen is isolated from healthy domestic cats, they are considered the major natural host of M. canis . It was generally thought that subclinical infections are common, especially in longhaired cats over 2 years of age. However, the prevalence of M. canis isolation from healthy animals varies greatly between subpopulations, and in many groups the prevalence is low
(Mignon & Losson, 1997). Therefore, M. canis should not be considered as part of the normal fungal flora of cats, and isolation from a healthy cat indicates either subclinical infection or fomite carriage (DeBoer &
Moriello, 2006).
1.9.1 Dermatophytes Epidemiology in Palestine
In 1989, Ali Shtayeh and Arda published their study on the epidemiology of dermatophytosis in Palestine. The study has shown that the dermatophytic mycobiota of the West Bank comprised about 14 dermatophytes with T. violaceum (anthropophilic dermatophyte) being the most predominant aetiological agent accounting for 34 50 % of total isolates; M. canis was the next most common aetiological agent accounting for 23% of total isolates(Ali Shtayeh and Arda ,1989).
An epidemiological study of tinea capitis was also carried out among 7,525 primary school children in the Nablus district in Palestine. Seventyfive cases of tinea capitis (1%) were mycologically proven. The incidence was higher in young children (1.4%) aged from 6 to 10 years than in older children (0.5%) aged from 10 to 14 years. Trichophyton 13 violaceum was the most common causative agent (82.7%) followed by M. canis (16%) and T. schoenleinii (1.3%). Also, other study of tinea capitis were carried out in 2000 among 8,531 primary school children in Nablus district in Palestine also the Trichophyton violaceum was the most common causative agent (65.5%) followed by M. canis (22.1%) (Ali Shtayeh et al. , 1998, 2002).
In Gaza the most common dermatophytic infection was tinea capitis (50.5%), followed by tinea corporis and tinea unguium (12.6% for each), and tinea versicolor (4.5%). Dermatophytes were significantly the most common isolated pathogens (28/34, 82.4%), followed by Candida spp. (5/34, 14.7%) and Malassezia furfur (1/34, 2.9%). Among dermatophytes, Trichophyton spp. was the most frequent isolate (14/34, 41.2%), followed by Microsporum spp. (13/34, 38.2%). The least isolated dermatophyte was Epidermophyton floccosum (1/34, 2.9%) (Al Laham et al ., 2011).
1.9.2 Etiological agents
Dermatophytes can be classified according to their usual habitat into anthropophilic, zoophilic and geophilic organisms. There are approximately 100, 000 species of fungi distributed worldwide. The majority of fungal infections seen in both temperate and tropical countries are superficial infections of the skin.
There are approximately 40 different species of dermatophytes, characterised by their capability to digest keratin and divided among three 14 genera: Trichophyton , Microsporum and Epidermophyton . A majority of superficial fungal infections of the skin are caused by five or six species of dermatophyte, of which Trichophyton rubrum is the most common (Aly,
1994).
The predominant species of dermatophytes vary according to their clinical localization. The management of tinea of the glabrous skin, caused by dermatophyte infections, is a common therapeutic problem for dermatologists (Szepietowski et al ., 2006).
Over 90% of tinea capitis dermatophytosis cases worldwide are caused by Microsporum canis (Sparkers et al. , 2000; DeBoer & Moriello, 2006). Others are caused by infection with Microsporum gypseum, Trichophyton mentagrophytes, Trichophyton quinckeanum, Trichophyton rubrum or other agents. With the exception of Microsporum gypseum, all produce proteolytic and keratolytic enzymes that enable them to utilize keratin as the sole source of nutrition after colonization of the dead, keratinized portion of epidermal tissue (mostly stratum corneum and hairs, sometimes nails).
By segmentation and fragmentation of the hyphae, dermatophytes produce arthrospores, which are highly resistant and adhere strongly to keratin also surviving in a dry environment for 12 months or longer (Sparkers et al ., 2000). In a humid environment, however, arthrospores are short lived. High temperatures (100°C) destroy them quickly. 15
1.10 Diagnosis
Other annular rashes are often confused with tinea infections. Eczema and psoriasis are commonly confused with tinea. Pityriasis versicolor occurs all over the trunk while Candida occurs as a flexural rash at extremes of age or in the immunocompromised, those with diabetes or patients on antibiotics. Treatment with topical steroids often causes confusion, making tinea less scaly and more erythematous (Rashid et al. , 2011) Steroid use also makes the 'active' edge and the inactive centre less distinct. Clinically the diagnosis can be difficult but, if it is a possibility, take scrapings for mycology. Other fungal infections look nothing like tinea. Other conditions to consider include: Contact Dermatitis, Seborrhoeic, and Erythrasma (Ellis et al. , 2000; Rashid et al. , 2011). Microscopy of skin and nail specimens may reveal hyphae and spores. Fungal culture can identify the species but is not always reliable and it can take six weeks to get results, so the use of molecular tool as PCR for identification is needed for fast and accurate diagnosis.
Ultraviolet light (Wood's light) is useful for tinea capitis especially. Fluorescence is produced by the fungus. Fluorescence is not seen with tinea corporis or tinea cruris. Rarely, a biopsy may be needed.
1.11 Identification of Dermatophytes
1.11.1 Conventional approaches
The diagnosis is not clinically obvious in many cases so the mycological analysis is required. This includes both direct microscopic 16 examination and cultures. First of all, clinical specimens have to be sampled according to localization and characteristics of the lesions. Direct microscopic examination is usually performed using clearing reagents
(KOH or Amman’s chloral lactophenol) (Koneman & Roberts, 1985). Histological analysis is an efficient method, but it is constraining for the patients and, as direct examination, it does not allow precise identification of the pathogen. Cultures are therefore needed, and specific culture media may be used to overcome the growth of rapidly growing contaminating moulds which may hamper the recovery of dermatophytes. Most dermatophytes colonies could be a presumptive identifying by using developed forms and pigmentation which appeared from a fungus colony depends on the used medium. In many reported literature Sabouraud dextrose agar (SDA) medium is conventionally used for comparative purposes. It is used to obtain colonies which can be compared to others (Ajello, 1974; Ameh & Okolo, 2004).
Identification at the species level which may be useful to initiate an appropriate treatment or for setting prophylactic measures relies on macroscopic and microscopic morphology. Subcultures on culture media which stimulate conditions and, for some species, the production of pigments, are often necessary. Additionally, in case of typical isolates, some biochemical or physiological tests may be performed such as the search for urease activity or the in vitro hair perforation test. However, their contribution to species identification is rather limited, and progress is still needed for the development of biochemical or immunological tests and 17 for the availability of molecular biology based kits allowing an accurate identification at the species level (Mochizuki et al. , 1997; Elewski, 1998; Moriello, 2001).
1.11.2 Molecular Biological Methods
Using molecular methods for the genotyping characteristic of the species of dermatophytes are more specific, precise, rapid and less likely to be affected by external influences such as temperature variations and chemotherapy and can be useful when the identification of a strain is not possible with conventional methods. PCR–RFLP (Blanz et al. , 2000;
Machouart Dubach et al. , 2001) and sequencing of ITS regions (Harmsen et al ., 1999) have been developed. However, most of these molecular approaches are used only in research laboratories. DNA of dermatophytes can also be detected directly in clinical samples (Machouart Dubach et al. , 2001). Indeed, a PCR– ELISA based kit using dermatophyte specific probes has been recently commercialized. It has been evaluated for onychomycosis, and its sensitivity was found to be close to that of mycological conventional techniques (Seebacher et al., 2008). This test allows the diagnosis of onychomycosis within only 24–48 h after sampling.
However, as no species identification is provided, cultures remain essential with such a kit. This could be definitively solved by the use of oligonucleotide hybridization methods which allow both direct detection of fungal DNA in clinical samples and identification at the species level and an oligonucleotide array has been developed recently which allows correct identification of 17 dermatophyte species (Li et al. , 2007). 18
Random amplified polymorphic DNA (RAPD) technique based on the polymerase chain reaction (PCR) has been one of the most commonly used molecular techniques to develop DNA markers. RAPD is a modification of the PCR in which a single, short and arbitrary oligonucleotide primer, able to anneal and prime at multiple locations throughout the genome, can produce a spectrum of amplification products that are characteristics of the template DNA. RAPD markers have found a wide range of applications in gene mapping, population genetics, molecular evolutionary genetics, and plant and animal breeding. This is mainly due to the speed, cost and efficiency of the technique to generate large numbers of markers in a short period compared with previous methods. Therefore, RAPD technique can be performed in a moderate laboratory for most of its applications. It also has the advantage that no prior knowledge of the genome under research is necessary (Meyer et al., 1997; Macura et al ., 2008). Due to advances in molecular biology techniques, large numbers of highly informative DNA markers have been developed for the identification of genetic polymorphism. In the last decade, the random amplified polymorphic DNA (RAPD) technique based on the polymerase chain reaction (PCR) has been one of the most commonly used molecular techniques to develop DNA markers and genotyping for different species, and among the dermatophytes, Microsporum canis constitutes the main species involved in infections of cats and dogs (Cabañes 2000; Brilhante et al., 2005). 19
The importance of using molecular epidemiology tools was once the question regarding the epidemiology of dermatophytes is the issue of reactivation or reinfection. Is an infection the result of a reactivation of a past infection or a new infection from the environment? This question is most easily answered by using molecular tools that have sufficient discrimination power to distinguish closely related species and strains.
Appropriate species and strain typing in most organisms usually focuses on the DNA/ rRNA gene cluster, using conserved regions of the DNA/rRNA or internal transcribed spacer (ITS). This type of analysis has been performed for many of the dermatophytes (Jackson et al. , 1999; Jackson et al. , 2000; Gupta et al. , 2001; Gaedigk et al. , 2003; Yazdanparast et al. , 2003; Rad et al. , 2005; Sugita et al. , 2006). However, the rRNA repeat is present in multiple copies in the genomes of most eukaryotes. Because of those repeats, PCR complications can occur associated with allelic variation between the repeats and mixing of alleles. Recent molecular epidemiology using DNA (non rRNA) methods has been performed for the most common dermatophytosis tinea capitis (Abdel Rahman et al. , 2006; Abdel Rahman et al. , 2007). The genetic relationships of fungi, was done by using DNA depending method. The random amplified polymorphic DNA (RAPD) method, have been described as molecular diagnostic tool by some authors to detect derrmatopytosis and polymorphism in some fungal strains (Bradley et al. 1999; Mukherjee et al. 2003). 20
1.12 Aims and Objectives
The aim of this study was to:
Determine the dermatophytes epidemiology including prevalence and
occurrence of causative agents of dermatophytosis in patients in Palestine; and to detect any changes in the etiological agents during the last 28 years.
Study the correlation between multifocal infections tinea pedis, tinea nail and tinea cruris.
Investigate genetic relationship within and between different etiological
agents using RAPD –PCR.
Genotyping identification for different dermatophytes species.
Study diversity during different dermatophytes species and within the
same species. 21
CHAPTER TWO MATERIALS AND METHODS 22 CHAPTER TWO
MATERIALS AND METHODS
2.1 Epidemiology of Dermatophytes Infections
2.1.1 Sample Collection
Samples were collected by Dr. Hisham Arda from his Dermatology Clinic in Nablus, 220 clinical specimens were collected from 188 patients with clinical signs of dermatophytosis. Demographic data was collected from all cases including: age, sex, profession, presence of animal in the patient’s environments.
2.1.2 Direct Examination
Direct microscopic examination of skin and hair specimens was performed after digestion in 10% (w/v) potassium hydroxide (KOH) with dimethyl sulfoxide (DMSO) aqueous solution, while nail specimens were digested using 20% KOH. Briefly, a portion of each sample was placed on a sterile empty petri plate and a few drops of KOH solution were added
(Lilly et al. , 2006). After 5 10 min for skin and hair samples and after 30 min for nail samples, part of this wet preparation was transferred to clean, dry microscopic slide and one drop of Lactophenol cotton blue was added then examined under low (100x) and high (400x) magnification power for the presence of arthroconidia, mycelium and /or spores (Panasiti et al. , 2006). 23
2.1.3 Cultures and Isolation of Dermatophytes
All specimens (irrespective of the negative or positive microscopic examination result) were cultured on Sabouraud’s dextrose agar (SDA) supplemented with antibiotics (chloramphenicol 0.05mg/ml, gentamicine, and cycloheximide 0.5mg/ml (Sigma Aldrich). The use of a selective medium is essential because skin and hair are susceptible to contain many bacteria or conidia of saprophytic fungi (Brun et al. , 2001). Cultures were either made on agar plates or agar slants. Cultures were incubated at 25 o C, and examined at least twice a week since some morphological traits appeared (Singh et al. , 2003), then identified using standard methods.
2.2 Genotypical Pattern of Dermatophytes Strains by using RAPD Analysis Primers
2.2.1 Fungal DNA Isolation
Eighty dermatophytes isolates were taken to do RAPD analysis, fifty three from Microsporum canis and twenty four from Trichophyton rubrum and three from Trichophyton mentagrophytes . A standardized inoculum was prepared from each isolate. Stock inocula were prepared from 10 days old cultures grown on Sabourod dextrose agar at 28 °C. Sterile normal saline solution (0.9%) was added to the agar slant, and the cultures were gently swabbed. The suspension of conidia and hyphal fragments was cultured in a sterile tube, contained 2 mL of Sabouraud liquid medium with
0.5 mg/l cycloheximide (Sigma) and 0.05 mg/l chloramphenicol (Sigma) 24 solution, twice for each sample and incubated with shaking for up to 8 days at 27°C. After that the pellet was harvested and suspended in 500 µl of lysis buffer (400mM Tris HCl [pH8.0], 60mM EDTA [pH8.0], 150mM NaCl,
1% sodium dodecyl sulfate) and left at room temperature for 10 min. Next, 150 µl of potassium acetate Kac [pH8.0] was added and tubes were vortexes and centrifuged (1min, 12,000xg). The supernatant was transferred to a new tube and 500 µl isopropyl alcohol was added. The DNA pellet was washed with 500 µl of 70% ethanol then dried for 5 min and 50 µl of S.D.H2O was added, then the concentration was measured by using multiscan plate biotech and all samples were diluted to 30ng/ µl (Brillowska Dabrowska et al., 2007). DNA integrity was performed by agarose gel electrophoresis. One percent agarose gel with 0.5 mg/ml ethidium bromide was used and gel was running at voltage 120V for 30 min in 100 mL from 1X TAE buffer (Tris–EDTA (0.001 mol/L). DNA samples were loaded as follows: 1 µl DNA sample, 2 µl from 6X sample loading buffer, and 7 µl sterile distilled water. The samples were loaded in the well by micropipette. The first well was the 1Kb DNA ladder 5 µl. The DNA band was visualized with a UV transilluminator and photographed.
2.2.2 RAPD Assays
RAPD assays were performed with the following random five primers: OPA 01 (5′ CAGGCCCTTC 3′); OPA 02 (5′ TGCCGAGCTG
3′); OPA 03 (5′ AGTCAGCCAC 3′); OPA 04 (5′ AATCGGGCTG 3′); and OPA 05 (5′ AGGGGTCTTG 3′) The reactions were performed in 25 25